The actress spent New Year's Eve at Lady Gaga's party at Fontainebleau Miami Beach.

And while the age difference between the two – Klitschko is 33 and Hayden is 20 – isn't anything peculiar for a Hollywood couple, the size difference for the pair is quite noticeable.

While Hayden stands just about 5 feet tall, Klitschko – who is the reigning IBF, WBO and IBO world heavyweight champion – towers over the actress at 6'6" and weighs in at approximately 245 pounds.

However, it's not the first time the pair has been photographed together.

In February 2009, the two posed on the red carpet together at a fundraiser at the Peninsula Hotel in Los Angeles.

Hayden and Klitschko also reportedly stepped out for a birthday party for Teen Vogue editor Carlos Lopez in Hollywood that same month – right around the same time the actress and her "Heroes" co-star Milo Ventimiglia (who is older than Hayden by 12 years) called it quits after two years of dating.